That would depend really. If you are talking about the older models like the Linksys WRT versions (WRT54G, WRT54GL and so on) then i would say Linksys hands down.
But i have heard many people say that their newer routers are not nearly as good.for current routers i would say D-Link, something like the D-Link DIR-655 Xtreme N Wireless Gigabit Router
But a company names Encore (can be bought on Newegg.com) also makes a pretty good and affordable router as well. Such as the ENCORE ENHWI-2AN3 802.11b/g/n Wireless Router With Repeater up to 300Mbps/ 10/100 Mbps Ethernet Port x4